One-step formation of multiple emulsions in microfluidics

Area of Science:

• Fluid dynamics
• Materials science
• Chemical engineering

Background:

• Multiple emulsions offer unique properties for various applications.
• Controlling shell thickness in multiple emulsions is challenging with conventional methods.
• Emulsification of complex fluids like viscoelastic ones requires specialized techniques.

Purpose of the Study:

• To present a robust microfluidic method for fabricating multiple emulsions.
• To demonstrate precise control over the shell thicknesses of these emulsions.
• To show the applicability of the method for emulsifying difficult-to-handle fluids.

Main Methods:

• Utilizing a microfluidic device to generate a coaxial jet of immiscible fluids.
• Employing a dripping instability to break the coaxial jet into multiple emulsion droplets.
• Precisely controlling the thickness of each fluid layer in the coaxial jet to dictate shell thickness.

Main Results:

• Successfully created multiple emulsions with a wide range of controllable shell thicknesses.
• Demonstrated the ability to tune shell thickness by adjusting fluid layer dimensions.
• Achieved monodisperse emulsion formation even with challenging fluids, including viscoelastic ones.

Conclusions:

• The developed microfluidic approach provides a robust and versatile platform for multiple emulsion fabrication.
• This method offers unprecedented control over shell thickness, expanding possibilities for emulsion-based technologies.
• The technique is effective for emulsifying fluids that are typically difficult to process, broadening its potential applications.